Study On Signal Processing Method For JTIDS-based Passive Bistatic Radar

As a bistatic/multistatic radar system,the passive bistatic radar can detect,locate and track the target by passively receiving external electromagnetic wave signals.Because of its strong concealment,low-altitude detection and anti-stealth,it is a radar system with broad prospects for development.As a time division multiple access information distribution system,the JTIDS integrates communication,navigation and identification.It has the characteristics of high transmission power and wide coverage in wartime.It is used as the radiation source of the external radiation source radar,which is beneficial to the target’s detection.Highprecision detection and construction of radar early warning network.Therefore,this paper studies the radar signal processing method of the external radiation source of the JTIDS.The main work of the paper is:1.The clutter suppression method of passive bistatic radar based on JTIDS signal is studied.Firstly,the system structure,signal structure and communication mode of JTIDS are analyzed and discussed in detail.Then,for different communication modes of JTIDS signals,the corresponding clutter suppression methods are studied: extended cancellation algorithm and improved extended cancellation algorithm.The validity of the above two clutter suppression methods is verified by simulation data respectively.2.The coherent integration method of passive bistatic radar based on fixed frequency JTIDS signal is studied.When a single JTIDS base station is used as the radiation source,due to the working mode of time division multiple access,the JTIDS signal has random empty time slots in the time domain,resulting in a certain non-uniformity of the fixed frequency JTIDS signal as a whole.Affected by the non-uniform structure of the JTIDS signal,the traditional coherent processing method is directly applied to the JTIDS external radiation source radar,and there is a problem of non-uniform sampling in the slow time dimension,which is characterized by a serious secondary peak in the Doppler dimension.Aiming at the above problems,this paper proposes a coherent integration method for fixed-frequency JTIDS signals based on non-uniform sampling.Detect target speed information.This method can effectively reduce the secondary peak response and improve the detection performance of the target.In addition,in order to solve the problem of large computational complexity of non-uniform Fourier transform data in the process of coherent integration,this paper proposes a fast implementation method of the above algorithm by using the cyclic shift theorem.3.The coherent integration method of passive bistatic radar based on frequency hopping JTIDS signal is studied.The frequency hopping JTIDS signal has the characteristics of frequency agility,which is characterized as a phase fluctuation problem during the coherent integration process,which destroys the continuity of the phase.Aiming at the problem of defocusing of moving target imaging in random frequency hopping signals,this scheme proposes an accurate velocity estimation method based on the phase quadratic difference method.Do a velocity estimate to get the velocity value on each distance unit.The motion compensation of the echo signal is completed by searching the velocity value obtained,and then the pulse synthesis of the target echo signal is performed in the slow time dimension,so as to realize the coherent integration processing of the random frequency hopping signal.At the same time,according to the characteristics of high repetition frequency of JTIDS signal,a distance fuzzing algorithm based on sliding matched filter is proposed.The method combines continuous wave processing and pulse system,and correlates with the reference signal during the continuous sliding process of the echo signal,thereby breaking through the limitation of the pulse repetition frequency on the detection distance,and synthesizing the unambiguous one-dimensional high range resolution profiles of the target.